Production of glycerol polyalkylethers as biofuel components

Glycerol di- and triethers obtained from glycerol, a by-product in biofuels production from vegetable oils (fatty acid methyl esters), can be used not only as an additive to biofuels or diesel oils, but also to gasoline, increasing its octane number. The presence of glycerol polyalkylethers in biofuel influences effectiveness of hydrocarbon combustion, by reduction of emission of noxious substances into the atmosphere. These ethers have also a positive influence on physicochemical properties of biofuel, by reducing its viscosity and temperature of cloudiness.

Process description

Glycerol polyalkylethers are obtained in a reaction of glycerol with olefins contained in the isobutene fraction (containing ca. 60 % isobutene), performed in the presence of an acid heterogeneous catalysts, at 80–120 °C and under pressure of 10–20 · 105 Pa. The process is carried out in the fixed-bed reactor. The product contains also isobutene dimers (isooctenes), a full-value raw material to produce isooctane, which can be separated from the ethers with flash distillation.

Advantages of the technology offered

Glycerol polyalkylethers are a very valuable additive to biofuels used in self-ignition engines.

The developed technology allows to dispose of market surplus of glycerol, derived from transesterification of triglycerides contained in vegetable oils.

In the Institute of Biofuels and Renewable Energy there were performed physicochemical investigation of the biofuel (from industrial process of rape oil transesterification) modified with tert-butyl glycerol ethers. A significant reduction in cold filter plugging point, viscosity reduction and increased cetane number was recognized.

Equipment

The glycerol ethers production proceeds in a column reactor with a catalyst bed, operating under pressure 10–20 · 105 Pa. Products can be separated by distillation in high-performance rectification columns.

The state of technology

The laboratory studies has been finished. The catalyst has been selected and the conditions to carry out the process have been established.